start_row = image[1][1]
How's perimeter calculated? for every blackpixel- check for pixels other than black in surrounding and add all non-black pixels
In this question,
For start black pixel: check for top, bottom and left and right for non black pixel:
value : 3 (all striked out pixels)
0,1,0
1,1,0
1,0,1
calculate as such for every connected black pixel and return cumulative perimeter = 3+2+2+2+3 = 12